{VERSION 5 0 "IBM INTEL LINUX" "5.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 " > " 0 "" {MPLTEXT 1 0 30 "# How to plot direction fields" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 "with(DEtools):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 64 "# Define the differential equation. TRY YOUR OWN EQUATION HER E!" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 32 "deq := diff(y(x),x)=x *sin(y(x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 36 "DEplot(deq, \+ y(x), x=-2..2, y=-1..1);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 " " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 73 "# To plot solution curv es, we must give initial data as a list of points." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 37 "inits := [[0,.5], [1,-.5], [-1,.25]];" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 43 "DEplot(deq, y(x), x=-2..2, y =-1..1, inits);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 62 "# If you want just the curve s and not the direction field, ..." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 56 "DEplot(deq, y(x), x=-2..2, y=-1..1, inits, arrows=non e);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "15" 0 } {VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 }{PAGENUMBERS 0 1 2 33 1 1 }